Question

Find the largest number of 3 digits which is a perfect square

Answer 1

​​​​​​You can approach this question using trial and error method
You can list out possibilities like this

30² = 900
31² = 961
32² = 1024

So we know that 961 is the last 3 digit number that is a perfect square (square of 31).
So the largest three digit number which is a perfect square is 961 (square of 31).